

A162191


Number of reduced words of length n in the Weyl group B_47.


0



1, 47, 1127, 18377, 229171, 2330589, 20127092, 151775596, 1019876970, 6201909910, 34546227171, 177996721677, 855147273198, 3856508701234, 16418497039281, 66308104573247, 255104779810273, 938387762441199
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OFFSET

0,2


COMMENTS

Computed with MAGMA using commands similar to those used to compute A161409.


REFERENCES

J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under PoincarĂ© polynomial.
N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)


LINKS

Table of n, a(n) for n=0..17.


FORMULA

G.f. for B_m is the polynomial Prod_{k=1..m}(1x^(2k))/(1x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.


CROSSREFS

Sequence in context: A010963 A234354 A161692 * A162456 A010999 A182019
Adjacent sequences: A162188 A162189 A162190 * A162192 A162193 A162194


KEYWORD

nonn


AUTHOR

John Cannon and N. J. A. Sloane, Nov 30 2009


STATUS

approved



